from collections.abc import Iterator
from itertools import tee
from typing import Tuple, List, Collection, Dict

def safehash(obj)->int:
  '''
  Tool to take a hash of an object in a safe way.
  The idea is that it intercepts non-hashable types
  and works around it.
  '''
  try:
      # first try the dumb way, because the safe way is expensive
      return hash(obj)
  except TypeError:
      # occurs for some built-in types
      if isinstance(obj, Collection): # list, set, tuple, .iterable
          return hash( tuple ( safehash(elt) for elt in obj ) )
      if isinstance(obj, Dict):
          return safehash( obj.items() )